This application is not related to any pending applications.
This application is not referenced in any microfiche appendix.
The present invention generally relates to air data sensing tubes such as, but not limited to, pitot tubes. In particular the present invention relates to a system and method to repair a permanently sealed air data sensing tube.
The instant invention advances the art and teaches a process whereby internally accommodated components of a permanently sealed air data tube can be replaced and thus extend the useful life of the tube.
As used herein, the terms xe2x80x9cpitot tubexe2x80x9d, xe2x80x9cpitot static tubexe2x80x9d, xe2x80x9csealed pitot tubexe2x80x9d, xe2x80x9cair data sensing probexe2x80x9d, xe2x80x9cair data tubexe2x80x9d, xe2x80x9cair data sensing tubexe2x80x9d, xe2x80x9cair data probexe2x80x9d, xe2x80x9cpitot probexe2x80x9d, xe2x80x9cpitot static probexe2x80x9d, xe2x80x9celectrically heated pitot tubexe2x80x9d, xe2x80x9caerodynamically compensated static pressure tubexe2x80x9d, xe2x80x9celectrically heated pitot static probexe2x80x9d, xe2x80x9cheated pitot tubexe2x80x9d, xe2x80x9cheated pitot static tubexe2x80x9d, xe2x80x9cheated probexe2x80x9d, xe2x80x9cpressure sensing instrument for aircraftxe2x80x9d, xe2x80x9cstrut mounted oval static tubexe2x80x9d, xe2x80x9cmulti-functional air data sensing probexe2x80x9d and xe2x80x9caerodynamic air data sensing probexe2x80x9d are used synonymously and interchangeably. The term xe2x80x9cstrutxe2x80x9d relates to an air data tube component which distances a probe component of the air data tube several inches away from a fuselage or other aircraft surface to which the air data tube is attached. The term xe2x80x9cprobexe2x80x9d when used individually relates interchangeably and synonymously to that component of an air data tube which contains a pitot pressure opening. The probe typically, though not necessarily, embodies one or more moisture drain and/or static port holes as well.
Air data tubes are used on aircraft for measuring certain parameters such as air speed, altitude, static pressure and other air measurement information and are typically mounted to the body or nose portion of an aircraft. Air data tubes usually contain an electrical heating element to melt off and prevent ice accumulations which can plug the air channel openings of air data tubes during flight.
Generally, air data tubes have a base section from which the tube""s strut component extends at an angle and terminates after connecting to the tube""s probe component. Many air data tubes are considered sealed single units, whereby the internal components, heating elements and probe are permanently sealed via conventional methods such as, but not limited to, welding, brazing or soldering. Oftentimes, these joints are hidden as the tube in its totality is plated or otherwise smoothed to allow for better aerodynamics. Consequently, the tube appears absent of any discernable means to access its internal components. In the event that a pitot pressure opening located at the end of the probe tip becomes damaged or eroded due to corrosion, pitot static ports along the probe section become damaged or eroded due to corrosion, a tube""s heating element(s) malfunctions, its pitot pressure line leaks or another tube connected component becomes damaged, the entire air data tube is discarded and replaced with an entirely new unit. Such lack of repairability results in increased costs as the entire unit is replaced, irrespective of whether the cause was due to a major or minor problem. Specifically, prior to the teaching of the instant invention, the art lacked teaching, disclosure and claim of a method of disassembly, component replacement/repair and reassembly of permanently sealed air data tubes. Most air data tubes currently used on commercial aircraft built by Boeing, McDonald Douglas and Airbus utilize such permanently sealed tube unit types.
As a large variety of aircraft models exist, and as specific air data tubes are designed for specific placement on specific aircraft models, the sizes, shapes internal components of air data tubes may vary considerably. However, it should be noted that most air data tubes operate in functionally the same manner. Different manufacturers promote different designs, and many known designs exist. There are many prior art patents for the design and manufacture of air data tubes. The present invention relates to the repair and overhaul of air data tubes that have been designed as unitary or sealed units. The teaching of the instant invention is the art of determining a suitable section or sections of the air data tube to allow for exposure and removal of its internal components, removal of the tube""s permanently attached heating element, removal of internal pitot and static tube components, and the replacement of unsuitable components with newly manufactured or refurbished parts, thereby restoring the overall unit to an airworthy status.
The present invention improves upon the art and fills a major void in the marketplace by enabling an aircraft owner to overhaul an air data tube with newly manufactured major components at a substantially reduced amount of cost. Savings to multiple aircraft owners such as a commercial airlines, or air cargo carriers can result in millions of dollars of cost savings each year. Most large aircraft have between 2 and 8 air data tubes mounted on them. The tubes have an average life span of between 3 and 7 years. From an aircraft owners point of view, use of this invention will transform the air data tube from what was once considered an xe2x80x9cexpendablexe2x80x9d item to a xe2x80x9crepairablexe2x80x9d item.
While numerous problems can cause a probe to malfunction and be taken out of service, a few common problems represent the majority of the fatal issues. They are:
1. The probe section and its various openings become worn from corrosion and wind damage. If the openings are worn beyond specifications allowed for by the OEM, the entire unit must be discarded and replaced with a new unit.
2. Malfunction of the heating element(s). Inability of the heating element to properly heat the probe section and strut of the air data tube can cause ice build up, closing the openings to the air data ports. Since the heating element is permanently attached to the inside wall of the probe section and strut, and since heretofore, the art was absent means by which to gain access to the internal portion of the tube without destroying it, the entire air data tube was discarded and replaced with a new unit.
The present invention provides for a method of elongating the useful life of these type of air data tubes by teaching a method for opening the air data tube body (strut), and removing components requiring repair or replacement. Having followed and completed the teachings of the instant invention, the air data tube may be returned to service, providing a substantial cost savings to an aircraft owner.
It is an object of the instant invention to provide a process by which permanently sealed air data tubes may be repaired and returned to useful service.
It is another object of the instant invention to teach a method by which a broachable area of an air data tube may be identified to allow access to its internally accommodated components for purposes of repair.
It is a further object of the instant invention to teach a singularly applicable process by which any model of a permanently sealed air data tube may be repaired and returned to useful service.
An additional object of the instant invention is to reduce costs associated with the replacement of non-repairable air data tubes.
Other objects and further scope of the applicability of the present invention will become apparent from the detailed description to follow, taken in conjunction with the accompanying drawings wherein like parts are designated by like reference numerals.